diaspora/app/controllers/api/openid_connect/clients_controller.rb

module Api
  module OpenidConnect
    class ClientsController < ApplicationController
      skip_before_action :verify_authenticity_token

      rescue_from OpenIDConnect::HttpError do |e|
        http_error_page_as_json(e)
      end

      rescue_from OpenIDConnect::ValidationFailed,
                  ActiveRecord::RecordInvalid, Api::OpenidConnect::Error::InvalidSectorIdentifierUri do |e|
        validation_fail_as_json(e)
      end

      rescue_from Api::OpenidConnect::Error::InvalidRedirectUri do |e|
        validation_fail_redirect_uri(e)
      end

      rescue_from OpenSSL::SSL::SSLError do |e|
        validation_fail_as_json(e)
      end

      # Inspired by https://github.com/nov/openid_connect_sample/blob/master/app/controllers/connect/clients_controller.rb#L24
      def create
        registrar = OpenIDConnect::Client::Registrar.new(request.url, params)
        client = Api::OpenidConnect::OAuthApplication.register! registrar
        render json: client.as_json(root: false)
      end

      def find
        client = Api::OpenidConnect::OAuthApplication.find_by(client_name: params[:client_name])
        if client
          render json: {client_id: client.client_id}
        else
          render json: {error: "Client with name #{params[:client_name]} does not exist"}
        end
      end

      private

      def http_error_page_as_json(e)
        render json: {error: :invalid_request, error_description: e.message}, status: 400
      end

      def validation_fail_as_json(e)
        render json: {error: :invalid_client_metadata, error_description: e.message}, status: 400
      end

      def validation_fail_redirect_uri(e)
        render json: {error: :invalid_redirect_uri, error_description: e.message}, status: 400
      end
    end
  end
end